In the Nicomachean Ethics, Aristotle asserts that the first step towards virtuous behavior is disciplined reception. Unless a student already possesses the habit of listening intelligently, he will be unable to attain the subsequent moral habits of justice, prudence, fortitude, etc. In the first vernacular translation of the Ethics, prepared in 1372 at the request of Charles V of France, Nicole Oresme takes this mandate seriously, seeking to teach his patron ethics by teaching him new ways to read and listen. To this end Oresme deploys more than 450 neologisms, defining many of them at length in a “Table des Moz Divers et Estranges (Table of Different and Strange Words)” and an elaborate program of marginal glosses. Together, these learning aids seek to expand and refine the king’s moral sense by doing the same to the language in which he thinks. Even more fundamentally, however, Oresme uses the design of his presentation copies, Brussels, Bibliothèque Royale MS 9505-06 and The Hague, Museum Meermanno MS 10 D-1, to inculcate new, text-based ways of making decisions. The manuscripts’ many codicological bells and whistles – including glosses and glossary, multiple prefaces and tables of contents, and two programs of miniatures designed by the translator himself – thus become tools for thinking. The codices themselves, I argue, become highly elaborated versions of Aristotle’s habit-inducing objects. Just as a lyre creates a lyre player through repeated playing and a building creates a builder through the work of construction, so Oresme’s Ethiques manuscripts seek to create an ethical monarch by adapting clerical reading practices for lay use. In particular, Oresme’s cycles of miniatures do not simply illustrate the text but become a primary means of training the king and his courtiers in its proper use.